1. Field of the Invention
The present invention relates to a fuel cell system including a fuel cell having a power generation cell. The power generation cell has a membrane electrode assembly. The membrane electrode assembly includes a cathode, an anode, and an electrolyte membrane interposed between the cathode and the anode. The fuel cell performs power generation as a result of electrochemical reactions occurring between an oxygen-containing gas supplied to the cathode and a fuel gas supplied to the anode. The fuel cell system further includes an oxygen-containing gas supply apparatus for supplying the oxygen-containing gas to the fuel cell.
2. Description of the Related Art
For example, a solid polymer electrolyte fuel cell employs an electrolyte membrane comprising a polymer ion exchange membrane. The electrolyte membrane is interposed between an anode and a cathode to thereby form a membrane electrode assembly (MEA). The membrane electrode assembly is sandwiched between a pair of separators.
A fuel gas flow field is formed between one of the separators and the membrane electrode assembly for supplying a fuel gas to the anode, and an oxygen-containing gas flow field is formed between the other of the separators and the membrane electrode assembly for supplying an oxygen-containing gas to the cathode. Further, a coolant flow field is formed between adjacent separators of each of the fuel cells for allowing a coolant to flow within areas alongside each of the electrodes.
In particular, in the case that the fuel cell is mounted in a fuel cell based electric vehicle, the fuel cell may possibly be placed in a fuel cell box. In such a fuel cell box, a fuel cell chamber for containing the fuel cell is formed, and a ventilation device is used for ventilating the fuel cell chamber. When entry of hydrogen into the fuel cell box from a hydrogen line of the fuel cell is detected, the ventilation device discharges the hydrogen to the outside of the fuel cell box by means of a ventilating fan.
Further, in a vehicle-mounted fuel cell, a limited space, such as the space underneath the vehicle floor or a front box, may be used as a fuel cell chamber that contains the fuel cell therein. For this purpose, the space in which the fuel cell is installed, i.e., the fuel cell chamber, needs to be ventilated in the same manner as in the case of a fuel cell box.
In this regard, for example, a fuel cell box ventilation device is known as disclosed in Japanese Laid-Open Patent Publication No. 2003-132916 (hereinafter referred to as “Conventional Example 1”). As shown in FIG. 6, the fuel cell box ventilator includes a three-way valve 1, a ventilating pipe 2, a ventilating fan 3, a discharge port 4, a hydrogen detection sensor 5, and a control device 6.
When hydrogen in a fuel cell box B is detected by the hydrogen detection sensor 5, the three-way valve 1 is operated in correspondence with the detection value. Therefore, air supplied from an air pump 7 to the fuel cell V is released into the fuel cell box B through the ventilating pipe 2.